feat: support FORGE_FOLDER_PATH env var for base path

crates/forge_config/src/reader.rs

@@ -49,8 +49,12 @@ impl ConfigReader {
         Self::base_path().join(".forge.toml")
     }
 
-    /// Returns the base directory for all Forge config files (`~/forge`).
+    /// Returns the base directory for all Forge config files.
+    /// Checks `FORGE_FOLDER_PATH` env var first, falls back to `~/forge`.
     pub fn base_path() -> PathBuf {
+        if let Ok(path) = std::env::var("FORGE_FOLDER_PATH") {
+            return PathBuf::from(path);
+        }
         dirs::home_dir().unwrap_or(PathBuf::from(".")).join("forge")
     }
 
@@ -164,6 +168,23 @@ mod tests {
         }
     }
 
+    #[test]
+    fn test_base_path_respects_env_var() {
+        let _guard = EnvGuard::set(&[("FORGE_FOLDER_PATH", "/custom/forge/path")]);
+        assert_eq!(
+            ConfigReader::base_path(),
+            PathBuf::from("/custom/forge/path")
+        );
+    }
+
+    #[test]
+    fn test_base_path_defaults_to_home_forge() {
+        let _guard = EnvGuard::set(&[]);
+        let path = ConfigReader::base_path();
+        let expected = dirs::home_dir().unwrap_or(PathBuf::from(".")).join("forge");
+        assert_eq!(path, expected);
+    }
+
     #[test]
     fn test_read_parses_without_error() {
         let actual = ConfigReader::default().read_defaults().build();

crates/forge_infra/src/env.rs

@@ -129,9 +129,7 @@ fn to_environment(fc: ForgeConfig, cwd: PathBuf) -> Environment {
         } else {
             std::env::var("SHELL").unwrap_or_else(|_| "/bin/sh".to_string())
         },
-        base_path: dirs::home_dir()
-            .map(|h| h.join("forge"))
-            .unwrap_or_else(|| PathBuf::from(".").join("forge")),
+        base_path: ConfigReader::base_path(),
 
         // --- ForgeConfig-mapped fields ---
         retry_config: fc.retry.map(to_retry_config).unwrap_or_default(),